MSM ultraviolet ray receiving element, MSM ultraviolet ray receiving device

An MSM ultraviolet ray receiving element comprising:

• a substrate;
• a first nitride semiconductor layer formed on the substrate and containing AlXGa(1-X)N (0.45≤X≤0.90);
• a second nitride semiconductor layer formed on the first nitride semiconductor layer, containing AlYGa(1-Y)N (Y≤1), and having a film thickness t (nm) satisfying 5≤t≤25;
• and
• a first electrode and a second electrode formed on the second nitride semiconductor layer and containing a material containing at least three elements of Ti, Al, Au, Ni, V, Mo, Hf, Ta, W, Nb, Zn, Ag, Cr, and Zr, wherein
• an Al composition ratio X of the first nitride semiconductor layer, and an Al composition ratio Y and a film thickness t of the second nitride semiconductor layer satisfy a following Expression (1);
• −0.009×t+X+0.22−0.03≤Y≤−0.009×t+X+0.22+0.03 (1), and
• the first electrode and the second electrode each include a comb-like portion from a base portion of which a plurality of teeth projects, and
• the teeth of the first electrode and the teeth of the second electrode are arranged to be alternately adjacent to each other as viewed in plan.

An MSM ultraviolet ray receiving element comprising:

• a substrate;
• a first nitride semiconductor layer formed on the substrate and containing AlXGa(1-X)N (0.45≤X≤0.90);
• a second nitride semiconductor layer formed on the first nitride semiconductor layer, containing AlYGa(1-Y)N (Y≤1), and having a film thickness t (nm) satisfying 5≤t≤25;
• and
• a first electrode and a second electrode formed on the second nitride semiconductor layer and containing a material containing at least three elements of Ti, Al, Au, Ni, V, Mo, Hf, Ta, W, Nb, Zn, Ag, Cr, and Zr, wherein
• an Al composition ratio X of the first nitride semiconductor layer, and an Al composition ratio Y and a film thickness t of the second nitride semiconductor layer satisfy a following Expression (1);
• −0.009×t+X+0.22−0.03≤Y≤−0.009×t+X+0.22+0.03 (1), and
• a two-dimensional electron gas layer with an electron density of 1×1011 cm−2 or more and 6×1012 cm−2 or less is present on an interface between the first nitride semiconductor layer and the second nitride semiconductor layer.